KR19990086182A - Rim type phase reversal mask for manufacturing semiconductor device and method of manufacturing same - Google Patents

Abstract

Disclosed are a rim type phase inversion mask for manufacturing a semiconductor device and a method of manufacturing the same. According to an aspect of the present invention, a mask substrate having a rectangular trench having a wide width and a narrow width is formed, and a phase reversal region in which the trench is spaced apart from the trench in a wide width direction of the trench and exposed on the mask substrate. And a light shielding film pattern formed on the mask substrate around the trench. The phase inversion region has a narrow width in comparison with the wide width of the trench in the wide width direction of the trench. Moreover, the phase inversion region has a rectangular shape and has a wide width in the wide width direction of the trench. The light shielding film pattern contacts the trench in the narrow width direction of the trench.

Description

Rim type phase reversal mask for semiconductor device manufacture and method of manufacturing same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor devices, and more particularly to a rim type phase shift mask and a method of manufacturing the same.

As semiconductor devices are highly integrated, it is difficult to perform a process of forming a pattern such as a small contact hole. In particular, as semiconductor devices are highly integrated with more than one giga DRAM, it is difficult to implement contact holes on a mask. Accordingly, there is a demand for a method capable of forming a smaller pattern on a semiconductor substrate as compared with a pattern such as a contact hole formed on a mask.

As one of these methods, a pattern forming method using a rim phase inversion mask has been proposed. In particular, the method of using the rim type phase reversal mask is effectively used as a method of forming an isolated contact hole. 1 and 2 are a plan view and a cross-sectional view for explaining a conventional rim phase inversion mask. 3 is a graph showing the amplitude according to the position of the light transmitted through the rim phase inversion mask.

Specifically, as shown in FIG. 1, the conventional rim type phase inversion mask includes a trench 30 through which light passes through the mask substrate 10. A light shielding film pattern 20 is formed around the trench 30, and the light shielding film pattern 20 is partially spaced apart from the trench 30 by a portion of the mask substrate 10 contacting the trench 30. Exposed Light passing through a portion of the exposed mask substrate 10 has a phase difference of about 180 ° with light passing through the trench 30. Thus, the exposed portion of the mask substrate 10 becomes the phase inversion region 15. At this time, the phase inversion region 15 has a constant width of ΔX and ΔY along the X and Y directions of the trench 30.

As shown in FIG. 3, the light passing through the rim phase inversion region 15 causes a destructive interference with the light passing through the trench 30 at the boundary of the trench 30. That is, the light passing through the trench 30 and the light passing through the phase inversion region 15 have opposite phases in amplitude as shown in FIG. As a result, the amplitude of the light introduced onto the semiconductor substrate has a phase opposite to each other as shown in FIG. 3 (b), and at the boundary as shown in FIG. 3 (c) due to mutual interference. The light intensity can be zero. As a result, the resolution or depth of focus of light selectively incident on the semiconductor substrate is improved to increase the resolution of the pattern formed on the semiconductor substrate.

At this time, the amount of light interfering with each other is determined by the line width or the like of the phase inversion region 15. Accordingly, in order to implement a contact hole having a uniform size, the width of the phase inversion region 15 should be uniformly formed. The method of forming the phase inversion region 15 is performed as follows. For example, the light shielding film pattern 20 spaced a predetermined distance from the trench 30 is formed by performing a photolithography process using electron beam exposure twice, that is, electron beam secondary exposure. As a result, a part of the mask substrate 10 that contacts the trench 30 is exposed to a predetermined width to form the phase inversion region 15.

In this case, the phase inversion region 15 is formed surrounding the trench 30. Furthermore, the phase inversion region 15 is formed to have a very narrow width. Therefore, it is very difficult to form the light shielding film pattern 20 so that the width of the phase inversion region 15 is constant. Therefore, a defect may occur in which the width of the phase inversion region 15 is uneven, and it is difficult to constantly adjust the width of the phase inversion region 15. As described above, if the width of the phase inversion region 15 is not uniformly adjusted to a constant width, the critical dimension of a pattern such as a contact hole formed on the semiconductor substrate may become uneven.

The technical problem to be achieved by the present invention is that the width of the phase inversion region can be formed uniformly, and thus the rim phase for manufacturing a semiconductor device capable of realizing an increase in the resolution or an improvement in the focal length of a pattern such as an isolated contact hole formed on the semiconductor substrate. To provide an inversion mask.

Another technical problem to be solved by the present invention is to form the width of the phase inversion region uniformly, so that a rim type for manufacturing a semiconductor device capable of realizing an increase in the resolution or an improvement in the focal length of a pattern such as an isolated contact hole formed on a semiconductor substrate. The present invention provides a method for manufacturing a phase inversion mask.

1 to 3 are schematic views illustrating a conventional rim typed phase shift mask.

4 to 6 are schematic views for explaining a rim type phase inversion mask according to an embodiment of the present invention.

7 to 13 are cross-sectional views schematically illustrating a method of manufacturing a rim type phase reversal mask according to an embodiment of the present invention.

14 to 16 are diagrams for explaining the effect of forming a contact hole by introducing a rim phase inversion mask according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100 mask substrate 150 phase inversion region

200: light shielding film pattern 215: light shielding film first pattern

300: trench 415: first photoresist pattern

455: second photoresist pattern

According to an aspect of the present invention for achieving the above technical problem, a mask substrate having a rectangular trench having a wide width and a narrow width is formed, and the mask substrate is exposed by being spaced apart at regular intervals in the wide width direction of the trench. A rim type phase reversal mask for manufacturing a semiconductor device, including a light blocking film pattern formed on a mask substrate around the trench and forming a phase reversal region, is provided. The phase inversion region has a narrow width in comparison with the wide width of the trench in the wide width direction of the trench. Further, the phase inversion region is rectangular and has a wide width in the wide width direction of the trench. The light blocking layer pattern contacts the trench in a narrow width direction of the trench.

Another aspect of the present invention for achieving the above technical problem is to form a light shielding film on a mask substrate. The light blocking film and the mask substrate are selectively patterned, and a rectangular trench having a wide width and a narrow width is formed on a lower mask substrate, and a light blocking film first pattern is formed to contact the trench. A part of the light blocking film first pattern that contacts the trench is selectively patterned in a wide width direction of the trench to expose a part of the mask substrate to form a light blocking film second pattern that sets a phase inversion region. The phase inversion region has a narrow width in comparison with the wide width of the trench in the wide width direction of the trench. The phase inversion region is rectangular and has a wide width in the wide width direction of the trench.

According to the present invention, it is possible to uniformly form the width of the phase inversion region to implement an increase in the resolution of the pattern or the focal length, such as an isolated contact hole formed on the semiconductor substrate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, embodiments of the present invention may be modified in many different forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the thickness of the film and the like in the drawings are exaggerated for clarity, and the elements denoted by the same reference numerals in the drawings mean the same elements. Also, when a film is described as being on or in contact with another film or semiconductor substrate, the film may be in direct contact with the other film or semiconductor substrate, or a third film is interposed therebetween. It may be done.

3 schematically shows a plane of a rim type phase reversal mask according to an embodiment of the present invention, FIG. 4 schematically shows a cross section according to VV ′ of FIG. 3, and FIG. 5 shows a cross section according to VI-VI ′. Shown schematically.

Specifically, the rim type phase reversal mask according to the embodiment of the present invention includes a mask substrate 100, a light shielding pattern 200, a phase reversal region 150, and the like.

A trench 300 is formed in the mask substrate 100, and light passes through the trench 300 to selectively expose a predetermined region of the photoresist film on the semiconductor substrate. In order to expose a certain area of the photoresist film in a constant shape, for example, a circular shape such as an isolated contact hole, a constant shape of the trench 300, for example, a wide width and a narrow width as shown in FIG. Branches are formed in a rectangle.

The light blocking layer pattern 200 is formed to surround the trench 300. The light shielding pattern 200 is formed of a chromium layer to selectively shield light incident on the mask substrate 100. The light blocking layer pattern 200 may contact only two opposite portions of the trench 300 and may be disposed on upper and lower portions of the trench 300 in a wide width direction of the two opposite portions, for example, a rectangular trench 300. It is formed at regular intervals apart. Therefore, a portion of the mask substrate 100 in contact with the trench 300 in the wide width direction is exposed. Light passing through a portion of the exposed mask substrate 100 has a phase difference, for example, about 180 °, with light passing through the trench 300. Thus, a portion of the exposed mask substrate 100 forms a phase inversion region 150.

The phase inversion region 150 is formed to have the same width as the narrow width of the trench 300. Therefore, the phase inversion region 150 is not formed in the narrow width direction of the trench 300 as shown in FIG. 5. Accordingly, the light blocking layer pattern 200 directly contacts an edge of the trench 100. Meanwhile, as illustrated in FIG. 6, the phase inversion region 150 is formed in the wide width direction of the trench 300.

As such, the phase inversion region 150 is formed only at two opposing portions of the trench 300. Accordingly, the trench 300 is formed to have a narrow width in one direction and to have a wide width in the other direction as appropriate. Since the phase inversion region 150 is formed in the wide width direction, an image formed on the semiconductor substrate by interference between light passing through the phase inversion region 150 and light passing through the trench 300 ( image) may have an enhanced resolution. In addition, an increase in focal length may be realized. Accordingly, a pattern such as a small sized isolated contact hole may be formed with an improved profile.

In addition, the phase inversion region 150 has a narrower width than the wide width of the trench 300 in the wide width direction of the trench 300. That is, ΔY of FIG. 4 is formed to have a narrower width than that of the trench 300. In addition, the phase inversion region 150 is formed in a rectangle having a wide width in the wide width direction of the trench 300.

The size of the image formed on the semiconductor substrate, that is, the size of the contact hole formed on the semiconductor substrate is determined by the size of the width ΔY of the phase inversion region 150. That is, as the size of ΔY increases, the amount of light that interferes with the light transmitted through the trench 300 increases. As a result, the size of an image transmitted through the mask substrate and formed on the semiconductor substrate is reduced. Therefore, a pattern such as a smaller sized contact hole can be formed.

Accordingly, the width ΔY of the phase inversion region 150 may be set wider by adjusting the wide width of the trench 300. Therefore, the process margin of the process of forming the phase inversion region 150, for example, the photolithography process using two electron beam exposures can be further secured. Accordingly, the width of the phase inversion region 150 can be maintained more uniformly, thereby preventing the width of the phase inversion region 150 from changing. Therefore, a pattern such as a contact hole formed on the semiconductor substrate may be more uniformly implemented, thereby preventing a change in the threshold line width of the pattern such as the contact hole. Furthermore, since the phase inversion region 150 is formed only in one direction of the trench 300, that is, in the up and down direction, it is possible to reduce the probability of a defect occurring in the formation process.

7 to 13 are cross-sectional views schematically illustrating a method of manufacturing a rim type phase reversal mask according to an embodiment of the present invention. 7 to 13 illustrate a cross section based on the cut line of VI-VI ′ of FIG. 4.

7 schematically illustrates a step of forming the light blocking film 210 on the mask substrate 100.

Specifically, the light shielding film 210 is formed on the mask substrate 100 made of a material through which light, such as quartz, can pass. Next, a first photoresist film 410 is formed on the light shielding film 210.

FIG. 8 schematically illustrates a step of forming the first photoresist pattern 415 on the light blocking film 210.

Specifically, the first photoresist film 410 formed on the light shielding film 210 is selectively exposed. At this time, electron beam exposure using an electron beam as a medium is used. Next, the exposed first photoresist film 410 is developed to form a first photoresist pattern 415 selectively selectively exposing the light blocking film 210.

9 schematically illustrates a step of forming the light blocking film first pattern 215 by patterning the light blocking film 210.

In detail, the light blocking film 210 exposed by using the first photoresist pattern 415 as an etch mask is etched and removed. As a result, the light shielding film first pattern 215 is formed to selectively expose a portion of the mask substrate 100 below the width of the first photoresist pattern 415.

10 schematically illustrates forming trench 300.

Specifically, a portion of the mask substrate 100 exposed is selectively etched using the first photoresist pattern 415 as an etching mask. For example, the trench 300 is formed by etching the mask substrate 100 exposed to a predetermined depth by using a dry etching method. At this time, the trench 300 is preferably formed in a rectangular shape as shown in FIGS. That is, it is formed to have a wide width and a narrow width. 10 and the like show cross sections in a wide width direction. Thereafter, the first photoresist pattern 415 is removed.

FIG. 11 schematically illustrates a step of forming the second photoresist film 450 covering the light blocking film first pattern 215 and the trench 300.

In detail, the second photoresist layer 450 is coated on the entire surface of the resultant from which the first photoresist pattern 415 is removed. In this case, the second photoresist film 450 is formed to a thickness such that the step difference caused by the light blocking film first pattern 215 and the trench 300 is overcome.

FIG. 12 schematically illustrates a step of forming the second photoresist pattern 455 on the light blocking film first pattern 215.

Specifically, the second photoresist film 450 covering the light blocking film first pattern 215 and the trench 300 is selectively exposed. At this time, electron beam exposure using an electron beam as a medium is used. Next, the exposed second photoresist film 450 is developed to form a second photoresist pattern 455 selectively exposing a portion of the light blocking film first pattern 215 that contacts the trench 300. In this case, a portion of the exposed light blocking film first pattern 215 may be a portion in contact with an edge of the trench 300 in the wide width direction of the trench 300.

FIG. 13 schematically illustrates a step of forming the light shielding film pattern 200 by removing a portion of the light shielding film first pattern 215 that is exposed.

In detail, a part of the light blocking film first pattern 215 exposed using the second photoresist pattern 455 as an etching mask is removed to expose a part of the lower mask substrate 100. The light shielding film pattern 200 is formed. A portion of the mask substrate 100 exposed is a region in contact with the edge of the trench 300 in the wide width direction of the trench 300. A portion of the exposed mask substrate 100 is used as the phase inversion region 150.

As described above, the phase inversion region 150 is formed in contact with the trench 300 in one direction of the trench 300, for example, in a wide width direction, as illustrated in FIGS. 4 to 6. In addition, the trench 300 is not formed in the narrow width direction. Therefore, the process is simple as compared with the case of forming a phase inversion region surrounding the trench 300. Accordingly, the probability that the width of the phase inversion region 150 is changed due to a process defect or the like is reduced.

In addition, as described with reference to FIGS. 4 to 6, the width of the phase inversion region 150 is determined according to the wide width of the trench 300. That is, when the size of the wide width of the trench 300 is increased, the width of the phase inversion region 150 may be increased to increase the amount of light interfering with each other. Accordingly, the size of the image formed on the semiconductor substrate can be kept small and the width of the phase inversion region 150 can be widened. Therefore, the process margin of the process of forming the phase inversion region 150 can be further secured, and a change in the width of the phase inversion region 150 can be prevented. Therefore, it is possible to prevent a change in the critical line width of the pattern such as an isolated contact hole or the like formed on the semiconductor substrate.

14 to 16 are schematic views for explaining the effect of using a rim phase inversion mask according to an embodiment of the present invention.

FIG. 14 schematically shows a top-view of a photoresist profile when using a rim phase inversion mask according to an embodiment of the present invention.

Specifically, a simulation is performed under the condition of introducing a rim type phase inversion mask according to an embodiment of the present invention having a layout such as a rectangular trench 300, a phase inversion region 150, and a light shielding pattern 200. do. At this time, the actual yarn uses a condition of μm as a unit of the X-axis and Y-axis of FIG. 14, and the exposure condition uses light having a wavelength λ of approximately 248 nm and a numerical aperture (NA) of 0.6. It uses a conventional lighting system. As a result of the inspection, a photoresist pattern of the circular contact hole 600 is implemented on the semiconductor substrate.

FIG. 15 shows the result of the actual inspection of FIG. 14 in a two-dimensional cross section.

Specifically, a two-dimensional cross section of the contact hole 600 is illustrated in FIG. 15 based on the result obtained by the inspection as described with reference to FIG. 14. According to FIG. 15, it can be seen that a photoresist pattern having contact holes of good profile on a vertical structure is implemented.

16 shows the results of the due diligence of FIG. 14 in a three-dimensional view.

Specifically, the result of the inspection as described with reference to FIG. 14 is shown in FIG. 16 in a three-dimensional image. It can be seen that the contact hole 600 is formed with a good pattern profile.

According to FIG. 14 to FIG. 16, as a result of introducing the rim type phase reversal mask according to the embodiment of the present invention and inspecting it, a contact hole 600 having a size of about 0.15 μm having a good profile can be realized. Able to know.

As mentioned above, although this invention was demonstrated in detail through the specific Example, this invention is not limited to this, It is clear that the deformation | transformation and improvement are possible by the person of ordinary skill in the art within the technical idea of this invention.

According to the present invention described above, a semi-rim type phase inversion mask is formed by forming a rectangular trench having a wide width and a narrow width and forming a phase inversion region in contact with the edge of the trench in the wide width direction of the trench. Can be formed. The phase inversion region may be formed to have a wider width, thereby further securing a process margin of the process of forming the phase inversion region.

Furthermore, since the phase inversion region is formed only in one direction of the trench, that is, in a wide width direction, it is possible to reduce the probability that a change in the width of the phase inversion region occurs compared to the case where the phase inversion region is formed to surround the trench. That is, the phase inversion region is not formed in the narrow width direction of the trench. Therefore, a process of forming a narrow phase reversal region is not performed, and process defects such as a change in width can be prevented. Therefore, it is possible to prevent the change in the width of the phase inversion region to maintain a uniform width, it is possible to uniformly implement the critical line width of the pattern, such as an isolated contact hole formed on the semiconductor substrate.

Claims (9)

A mask substrate having rectangular trenches having a wide width and a narrow width; And A rim type phase inversion for manufacturing a semiconductor device, comprising: a light shielding film pattern formed on a mask substrate around the trench to form a phase inversion region spaced apart from the trench by a predetermined interval in a wide width direction of the trench; Mask. The rim type phase reversal mask of claim 1, wherein the phase inversion region has a width narrower than that of the trench in a wide width direction of the trench. 3. The rim type phase reversal mask of claim 2, wherein the phase inversion region is rectangular. The rim type phase reversal mask of claim 3, wherein the rectangular phase inversion region has a wide width in a wide width direction of the trench. The method of claim 1, wherein the light shielding pattern is A rim type phase reversal mask for manufacturing a semiconductor device, wherein the trench is in contact with the trench in a narrow width direction of the trench. Forming a light shielding film on the mask substrate; Selectively patterning the light blocking film and the mask substrate, forming a rectangular trench having a wide width and a narrow width on a lower mask substrate, and forming a light blocking film first pattern in contact with the trench; And And selectively patterning a part of the light shielding film first pattern in contact with the trench in a wide width direction of the trench to form a light shielding film second pattern exposing a portion of the mask substrate to set a phase inversion region. A rim mask manufacturing method for manufacturing a semiconductor device. 7. The method of claim 6, wherein the phase inversion region has a width narrower than that of the trench in the wide width direction of the trench. 8. The method of claim 7, wherein the phase inversion region is rectangular. The method of claim 8, wherein the rectangular phase inversion region has a wide width in the wide width direction of the trench.